Hammertoes are perhaps the most common foot deformity. Hammertoes are a deformity in which there is a contraction of the lesser toes (all the toes except the big toe). The toes begin to gradually curl into the ball of the foot. This can lead to painful corns, as well as pain with shallow shoe use. It can also eventually lead to pain in the ball of the foot.
Hammertoes develop mainly due to genetic variations of one’s foot structure. This condition is seen with those who have flat feet, and those who have high arches. The typical cause of hammertoes has much to do with imbalance of muscles flexing and extending the toes, with the muscles flexing the toes ultimately winning. This is seen in flat and flattening feet. High arches create hammertoes in a somewhat different manner, with the extending muscles dominating the process. Other causes of hammertoes could include muscle or tendon injury, as well as neuromuscular disease like cerebral palsy. There are several other toe contractions that resemble hammertoes, but are slightly different. These include claw toes and mallet toes. These types of toe contractures will be discussed elsewhere.
As the toes contract, the joints become prominent on top, and pressure from the shoe material can irritate the prominent skin. When two hammertoes are placed side by side they can irritate each other from their contact. Either way, the result of this irritation is a corn, also known as a hyperkeratosis. Hyperkeratosis are normal parts of the skin’s defense mechanism from pressure. However, when these become thick enough, pain can develop. In some people, skin wounds can even develop underneath the corn as the underlying skin dies from the pressure. Hammertoes can also exert pressure on the long bone that comes before the toe begins. There are five metatarsal bones in the foot, and each connect to the base of a toe at the ball of the foot. As the toe contracts upward, the base of the toe can push down on the end of the metatarsal, driving it downward towards the ground. The results of this pressure on the skin from underneath, combined with the ground pressure externally, is a painful callus (same tissue as a corn) under the ball of the foot. The pressure from the toe also lead to instability of the joint itself.
Hammertoes cannot fix themselves or be ‘stretched’ back into position. Non-surgical measures are used to decrease pressure to the skin by employing padding, deep shoes, and corn/callus care to de-thicken skin. The toe may have less pain on a temporary basis, but the deformity remains. Surgery actually returns the toe to a normal, generally straight position so that the shoe stays away from the skin, and the toes do not rub on each other through their combined bone prominence. Generally all hammertoe surgery is outpatient, same-day surgery, and the procedures can vary depending on the underlying cause of the deformity. For the most part, recovery is generally quick for foot surgery, with resumption of regular shoe use taking place in a month or less. The only exception is when toes have to be fused. Most patients can still walk normally during most of the recovery period, with the assistance of a hard-soled surgical sandal. Complications are usually minimal and infrequent, although infection, numbness, instability, and long term swelling of the toe are the most common complications when they do occur.
The traditional technique to correct a hammertoe involves making an incision on the top of the toe and removing a small section of bone at the most prominent joint, as well as releasing or lengthening specific ligaments, tendons and soft tissue that act on the bones if the contracture is not fully relaxed when the bone is removed. If the toe is still contracted upward at its base, the surgery proceeds down to that area and more joint tissue is released. If the metatarsal bone is too long and the toe won’t settle back into position, a shortening procedure may be performed on the long bone to release pressure on the base of the toe and allow it to become straight again. Once the procedure is finished and the toe is determined to be straight, an external metal wire is used to hold the position for several weeks while the toe heals.
Another common procedure to correct a hammertoe involves fusing the toe joint together. as opposed to simply removing bone This is performed on the joint if it is very rigid, or if the contracture is due to a progressively present neuromuscular disease that will re-contract the toe later on if it is not made more rigid. Some surgeons also prefer this technique for all their hammertoes, as it results in a predictably stable toe. The bones are often fused together using implants across the joint that compress the space. Another extra procedure involves transferring one of the tendons that flex the toe over to the top of the toe, the result of which is now the tendon will now push the toe downward instead of curling and moving it upward. The little toe may require a different approach altogether, as it is often curled to the side as well as contracted. In this case, a special incision is used to rotate the toe back to a proper position, or the little toe is partially fused to the toe next to it to keep the rotation from occurring again.
Hammertoe surgery healing takes place over the course of a month or so, with only moderate pain that is generally well controlled by pain medication or anti-inflammatory medication. The skin heals within two weeks, although toe swelling can take several months to go down. Most people see long-lasting correction, although a small number can have a partial return of the contracture if the forces acting on the toe are too strong.